title: [Reductive degradation of chlorophenols in aqueous solution by gamma irradiation].
abstract: Because chlorine is an electron withdrawing group, the highly chlorinated phenols may react quickly with hydrated electrons rather than with hydroxyl radicals. The process of reactions of four chlorophenols (4-CP, 2-CP, 2,4-DCP, 2,4,6-TCP) with e(aq)(-) was investigated in aqueous solutions by detecting the concentration of CPs, Cl- and intermediates. In the e(aq)(-) reductive system, the experimental results showed that the order of four kinds of chlorophenol degradation and dechlorination was 2,4,6-TCP > 2,4-DCP > 2-CP > 4-CP. The greater the chlorine content was the higher reactivity of hydrated electrons towards chlorophenols was. Furthermore, hydrated electrons may preferentially attack the ortho-position of chlorine atom rather than the para-position of chlorine atom. Phenol and Cl- were detected as the final product of the reductive reaction. Additionally, processes of degradation and dechlorination of CPs were observed as the pseudo-first-order kinetics. The reaction constant of degradation of 4-CP, 2-CP, 2,4-DCP and 2,4,6-TCP were 0.154, 0.253, 0.750 and 1.188 kGy(-1), respectively. Meanwhile, the dechlorination of 4-CP, 2-CP, 2,4-DCP and 2,4,6-TCP were 0.137, 0.219, 0.251 and 0.306 kGy(-1), respectively.
authors.affiliation: Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China. yunxiapeng@foxmail.com
authors.forename: Yun-Xia
authors.initials: YX
authors.lastname: Peng
authors.forename: Shi-Jun
authors.initials: SJ
authors.lastname: He
authors.forename: Wen-Qi
authors.initials: WQ
authors.lastname: Gong
authors.forename: Jian-Long
authors.initials: JL
authors.lastname: Wang
mesh_terms: D002733:Chlorophenols / Q000302:isolation & purification* / Q000528:radiation effects; D003037:Cobalt Radioisotopes; D005720:Gamma Rays; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification* / Q000528:radiation effects
chemical_list: D002733:Chlorophenols; D003037:Cobalt Radioisotopes; D014874:Water Pollutants, Chemical